1. Field of the Invention
The present invention relates to a window regulator including a drum mounted to of an inner panel of a door on a surface facing an outer panel and being capable of rotating in the forward direction and the reverse direction; an annular wire partly wound around the drum; a wire guide member mounted to the inner panel of the door on the surface facing the outer panel for guiding the wire so that the wire is arranged along the direction of upward and downward movement of a window glass; and window glass mounting means for mounting the window glass to the wire at a portion along the direction of upward and downward movement of the window glass, in which the window glass is moved upward and downward by moving the wire by rotating the drum in the forward direction or the reverse direction.
2. Description of Related Art
As an example of a window regulator using a drum, there is the one as shown in FIG. 6. In the drawing, a drum 3 on which a wire 1 is wound is provided in a drum housing 5, and the drum housing 5 is attached to an inner panel of a door on a surface facing an outer panel. The drum 3 is adapted to be rotated by a motor 7 in the forward direction/reverse direction.
A guide rail 9 is mounted to the inner panel of the door on the surface facing the outer panel along the direction of upward and downward movement of a window glass. A slider 11 movably engages the guide rail 9, and the window glass, not shown, is mounted to the slider 11. Therefore, the slider 11 functions as window glass mounting means.
An upper pulley 13 is provided on the upper portion of the guide rail 9, and a lower pulley 15 is provided on the lower portion thereof. The upper pulley 13 and the lower pulley 15 function as wire guide members which guide the wire 1.
One end of the wire 1 is fixed to the slider 11 via the upper pulley 13. The other end of the wire 1 is fixed to the slider 11 via the lower pulley 15.
A wire sag compensating mechanism 20 will now be described.
Outer tubes 21 for allowing passage of the wire 1 therethrough are arranged between the drum 3 and the upper pulley 13 and between the drum 3 and the lower pulley 15. One end of the each outer tube 21 is fixed to a member on which the upper pulley 13 and the lower pulley 15 are provided. The other end, that is, the end on the drum 3 side of the outer tube 21 is provided with a slide bush 23 for allowing passage of the wire 1 therethrough as shown in FIG. 7. The slide bush 23 movably engages a cylindrical tube holding portion 25a formed on a base 25 provided with the drum 3. Therefore, the tube holding portion 25a functions as guide means which guides the outer tube 21 on the drum 3 side in the axial direction of the outer tube 21. The outer tube 21 is urged in the direction of being pushed out from the tube holding portion 25a by a spring 27 as urging means arranged in the tube holding portion 25a and abutted at one end to the bottom of the tube holding portion and at the other end to the slide bush 23 of the outer tube 21. When the wire 1 sags, the outer tube 21 is pushed out by an urging force of the spring 27 so that a wire path between the base 25 and the upper pulley 13 and a wire path between the base 25 and the lower pulley 15 are expanded, thereby absorbing the sag of the wire 1.
When the drum 3 is rotated in the forward direction or the reverse direction by driving the motor 7, and hence the wire 1 is moved, the slider 11 moves along the guide rail 9 and the window glass is moved upward or downward (for example, see Patent Document 1).    Patent Document 1: JP-A-9-144424